Drill for dental purposes



Patented June 14, 1932 r i UNITED STATES PATENT OFFICE RUDOLF IEUNKE, OF DUSSELDORF, GERMANY DRILL FOR DENTAL PURPOSES Application filed February 20, 1930, Serial No. 430,024, and in Germany November 5, 1929.

The invention relates to dental drills which teeth. Beyond the point 7 all cutting edges are provided with a plurality of cutting edges are equidistant from the centre of the drill, distributed upon the periphery of the drill, in consequence whereof the drill may be used two of which cutting edges are formed in at an angle to the drill axis for milling purone continuous drilling edge passing over the poses. 55 crown of the drill. As with such drills all I clalm: the cutting edges are simultaneously in op- A dental drill having asubstantially sphereration a comparatively great feed pressure ical head provided with a continuous drillis acquired when boring in axial direction. ing edge the center of the radius of which 10 This drawback is obviated with the ordinary is coincident with that of the head and also 66 two-edged drills, which, however, owing to having cutting edges at opposite sides of said the absence of guide teeth, jump and rattle continuous drilling edge, the center of the upon the hard tooth substance. radius of said cutting edges on the crown According to the invention the advantages portion of the head being eccentric to that of the types of drills referred to are com- 0f the said continuous drilling edge, so that bined by arranging the said continuous drillsaid lateral cutting edges lie wholly within ing edge to project in axial direction relathe outline of the head and its crown portion tively to the remaining guide teeth. It thereand sald drilling edge projects beyond said fore acts in the manner of an ordinary twocutting edges at the crown portion of the edged drill while boring axially, jumping of head and axially or" the drill. 76 the drill being prevented by the guide teeth. In testimony whereof I have hereunto set Further there is the advantage that the drill my hand this 28th day of January, A. D. formed in the novel manner according to 1930. the invention may be used at an angle to the RUDOLF FUNKE. drill axis in the manner of a milling tool.

On the drawing is shown by way of example one form of the new drill.

Fig. 1 shows a perspective representation. Fig. 2 is a side elevation. 30 The drawing illustrates a drill with spher- 80 ical head the cutting teeth 1 of which are uniformly distributed upon the periphery of the drill. Two edges 2 are formed in one continuous drilling edge 3 passing over the crown of the drill. 85

As shown particularly in Fig. 2 the edge 3 projects relatively to the edges 1 in axial direction, this being attained for example by placing the centre of the radius 4: of the crown portion of the edges 1 eccentrically towards the shank of the drill in respect of the centre of the radius 5 of the cutting edges 8. Contrariwise the cutting edge 3 may project beyond the spherical form of the drill head. The flutes 6, one at each side of the continuous drilling edge 3, serving for the removal of chips are somewhat larger than the remaining flutes, so that they are better adapted for the removal of chips 59 thus preventing choking of the adjacent 

